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Actual test of engine oils...
3

Actual test of engine oils...

Actual test of engine oils...

(OP)
Though the report looks a bit dated, it's nice to see some actual test results to balance marketing claims. The winners in absolute performance (not performance vs price) are Royal Purple Racing 51 and Penrite Synthetic 5. Both survive over 295,000 psi!
http://www.animegame.com/cars/Oil%20Tests.pdf

RE: Actual test of engine oils...

Problem being, as with ALL of these tests, is that the conditions prevailing in a test rig that tests one or a small number of properties of the oil aren't necessarily representative of conditions prevailing inside an actual engine ... and some engines test some performance aspects differently than others (e.g. some engines have sliding-follower valve lifters and others have roller lifters), and differing usage patterns on the SAME engine can test some performance aspects differently than others.

RE: Actual test of engine oils...

Quite so

"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz

RE: Actual test of engine oils...

Go for what the engine manufacturer recommends...

RE: Actual test of engine oils...

Since RodRico maybe the engine manufacture??? He is the designer so??? Hoxton?? any other ideas?
There are some good additives that will also do as well under extreme pressure tests.

RE: Actual test of engine oils...

2
this "test" is utter nonsense. it only shows that different engine oils show different antiwear properties in the indeed common Falex test. however, that test was never designed to test engine oils, but as a fast screening test whether antiwear properties are present in a lubricating oil under conditions that somewhat mimic the circumstances in gear lubrication. thus a simple and cheap SAE 80W90 API GL5 gear oil most likely would have yielded far better results then the engine oils "tested" - which surely does not mean that you should put a gear oil in a engine...

RE: Actual test of engine oils...

Yeah that test is only for show.

It has no place in actual laboratory research of lubricants. We were given one of those rigs here and it sits in our back room collecting dust because it's so worthless at testing oil. Besides the fact that there is no ASTM standard for the rig, it is extremely, and I do mean extremely, easy to modify a formula to perform amazingly on that test and either offer no additional protection, or actually decrease real world engine protection at the same time.

Andrew H.
www.mototribology.com

RE: Actual test of engine oils...

4-Ball Wear (ASTM D4172) is a much better screening test. It catches a lot of flak from enthusiasts because it doesn't really imitate contact points in an engine, but it still has its place in development. In my opinion, it offers an easy, fast screening method for low pressure wear of sliding contact points and it gives in indication of general wear protection even if it doesn't simulate engine parts exactly.

That being said, it is only one aspect of performance. They did produce some "study" white papers of overall performance, but their methods and reporting have been called into question over those reports for years. The best thing would be an independent study from an unbiased source, but understandably, no one seems willing to conduct and fund such a thing.

Andrew H.
www.mototribology.com

RE: Actual test of engine oils...

(OP)
MotoLuber,

I started looking into this because my engine is cam-driven. I'm putting 160,000 lbf on a polished cam track of Maraging 350 steel (319,000 psi yield). Analysis indicates I've got 50% yield margin on the metal contacts, but I was worried about the oil. The only other lubricated surfaces I have are roller bearings and piston rings, and they don't concern me as much. The comments from Amsoil regarding moly wear and evaporation with Royal Purple (as well as BBB comments) concern me. Increased wear and evaporation may not concern racers who run a race and rebuild, but they would certainly be a problem in normal consumer use.

Krytox is interesting to me because it appears to have good performance at high temperature/load and doesn't burn (www2.dupont.com/Lubricants/en_US/assets/downloads/Krytox_Overview_H-58505-3_19april2010.pdf). My engine is a two-stroke using a dry sump lubrication system with oil injected between the rings. An oil that allows higher cylinder wall temperature improves efficiency, and the fact that Krytox doesn't burn would alleviate the normal two-stroke concerns about emissions from oil in the ports. Krytox is fantastically expensive, but it may be worth it insofar as my oil consumption is low and filtering effective. Comments?

RodRico

RE: Actual test of engine oils...

Your application is pretty atypical, so you are probably right not not concern yourself with the more trivial properties.

Chemically inert and non-flammable seem like the way to go in a system like you are describing. If all goes as planned, it seems viable. I don't know the price of Krytox, but as long as you can justify the cost with the benefit, I'd say it is a very good option to further investigate.

Andrew H.
www.mototribology.com

RE: Actual test of engine oils...

Oh I also did want to point out something in regard to your link to the Amsoil vs Royal Purple report. The test conditions Amsoil uses for the 4-ball wear are not the standard conditions for the ASTM method, so the repeatability and reproducibility are unknown under those conditions.

I really have no idea why they run under those conditions, but they do it for most of the products I've looked at data sheets for. I would have to assume that they get better results under the 1800 rpm, 150oC, 60 kg conditions than they do under the standard: 1200 rpm, 75oC, 40 kg conditions. It's always made me just kind of pass over their results with regard to that test though.

Andrew H.
www.mototribology.com

RE: Actual test of engine oils...

(OP)
My prototype will not be optimal in several areas because I'm not doing full blown modeling and simulation (tools are too expensive for my taste), but I want to show good performance with minimal risk, so Krytox is pretty attractive. Once I have a well working prototype, I will be able to invest more, better refine the design, and transition to less exotic oil.

I was planning to spray oil on the cam tracks, but I'm now thinking I might be better served by using felt wipers to spread a thin film of oil on them. The loads switch between the inner and outer surface during precise locations on the profile, and I can put the felt in regions where the surface is unloaded. Properly designed, this approach should allow me to apply the idea amount of oil and reduce consumption... a goof thing since it apparently costs $500 per kg! (https://www.walmart.com/ip/KRYTOX-GPL-107-Oil-GPL-...)

RE: Actual test of engine oils...

There are so many conflicting messages concerning engine oil that I don't know what to think.

I tend to suspect that the stronger the marketing message, the weaker the underlying product actually is under actual real world conditions. Worst offenders (in no particular order): Lucas, Amsoil, Royal Purple.

I have a motorcycle engine that I recently took apart and rebuilt due to a high oil consumption issue (whose origins were not related to the oil itself). For the last 20,000 km I've been using the cheapest 20w50 that I could find on the shelf because the engine was incinerating it anyhow. The con-rod and main bearings were fine. Pistons were fine. Camshafts were fine. Lifters were fine. (Piston ring and cylinder wall conditions were not fine, but again, this wasn't because of the oil.)

RE: Actual test of engine oils...

Yes, I find it very unfortunate how most companies choose to portray their products. A lot of hype with little to no data, or, even worse, misleading data meant to basically trick customers.

That's partly why I started my website; to try to demystify the topic for people who are interested in knowing the finer details.

Andrew H.
www.mototribology.com

RE: Actual test of engine oils...

my observation is for the most part it doesn't matter that much. choosing a random oil from an auto parts store is unlikely to cause you any issues

RE: Actual test of engine oils...

(OP)
Brian,

What happened to the rings and walls ?

Rod

RE: Actual test of engine oils...

I have used Krytox, just be aware that when it breaks down fluorides are released, this can result in corrosion issues.
We also used to buy straight PAO base oils. You can select the viscosity and fine tune. Then if you want to you can add a EP additive package (we ran without one).

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

RE: Actual test of engine oils...

re the engine I just had apart and put back together ... long story, but I've got time, so why not.

Engine in question is that of a 2004 Kawasaki ZX10R which I've owned since new.

I had it apart originally with about 70,000 km on it. At that time, it was running well, but it had become apparent that this specific engine in that specific year had a "ticking time bomb" inside it because a set of thrust washers in the alternator (which is internal, in this engine - not like cars) were not properly heat treated. There was a kit available to replace them with washers with different heat treatment ... but no recall, because the original washers generally lasted long enough to get through warranty. The kit was "race kit" parts. The issue was quietly fixed for the 2005 model year.

While there was a theoretically possibility of doing this in-frame, I opted to go through the whole engine and fix a couple of other known weaknesses - like the valve retainers, which I replaced with those from the 2008-2010 model, which are stronger. (the '04 - '07 retainers are known to crack from time to time) And might as well do some upgrades of course while we are in there ...

And that brought up the question of what to do with the cylinder walls, which are plated aluminum. I know what to do with cast-iron cylinder walls but opinions of what to do with plated aluminum cylinders ran the gamut from "nothing", to "clean them up with red Scotchbrite and call it good", to "just glaze-break them as normal", to "glaze-break them but you have to use a special tool made of X", to "no honing tool short of diamond will touch them", to "you have to send it out to this specialty company that reworks them" (at significant cost and lead time). Of course, everyone who has an opinion on this matter says that everyone else is wrong, and there's no way to tell from my end of the internet who's speaking the truth and who's spouting words that they read somewhere.

At that time (70,000 km) I opted to do what the factory service manual said ... Nothing. Put in new rings and go. I figured that if I didn't do anything but should have, I could always go back in there and do it again, whereas if I did something but shouldn't have, there was no going back.

Well, as it turned out (and not that I was terribly surprised), that was a mistake. The cylinder walls were too smooth for proper ring break-in. It burned oil from the get-go. It ran OK but never really made the power that it should have for what else was in there (Wossner high-compression pistons, select-fit head gasket for proper squish clearance, degreed cams, etc).

I've since put another 25,000 km on it, adding about a litre of oil every 1000 km the whole time.

So this winter's project to keep me busy, was to pull it apart and go through it again. Of course, the same question comes up ... what to do with the cylinder walls.

I know what proper cylinder wall finish looks like and feels like on an engine with cast-iron liners and I have the tool to do it. So, given that I now knew that I had to do "something", I started with what I figured would be the least-aggressive things to do among all the things that the internet suggests to do, and work up until I found something that worked.

In order ...

Scotchbrite did absolutely nothing except wipe off the slight bit of carbon built up above the top travel limit of the upper compression ring.

Emery cloth wrapped around the arms of a normal 3-arm glaze-breaker did nothing.

Aluminum-oxide 240 grit sandpaper wrapped around the arms of a normal 3-arm glaze breaker seemed to do a little bit but not something that I was happy with.

The normal 3-ring glaze breaker, as is without any other nonsense, well lubricated and turned with my fingers only just to see if it would touch the surface ... did something. So I chucked it up in the drill and gave it a quick de-glaze following the normal process as for cast-iron liners except only for a couple of seconds because you do NOT want to wear through the coating.

The cylinder walls look OK. They are visibly scratched up in a roughly 30 degree crosshatch pattern. No hand tool will achieve the uniformity of how the factory does it on their machine. But it's crosshatched now.

I've had the engine running and it seems OK. Weather (winter) precludes any sort of test-ride. I plan on not starting the engine again until such time as I can beat on it a little to encourage the piston rings to seat within the first 50 km or so. That could still be a couple of months away.

Even if this doesn't achieve "perfection" ... even if it still uses oil but only half as much ... I'll be happy with that.

RE: Actual test of engine oils...

(OP)
Brian,

I thought those Nikasil coatings were supposed to be *permanently* cross-hatched because the rings are made of much softer material. I did a bit of research and found the same as you... too much conflicting advice to form a solid conclusion. The most credible reference I found was the one at http://www.nzcylinders.com/Cylinder%20honing.html . It sounds pretty similar to what you did, so I think your optimism is founded. Fingers crossed !

EdStainless,

I thought one must push Krytox past it's recommended operating temperature (350C for XHT-500 oil) before breakdown occurs and fluorinated compounds released ( https://www.fastenal.com/productimages/supplementa... ). Did you see problems below 350C ?

Rod

RE: Actual test of engine oils...

Krytox is stable up to those temperatures- but remember that the breakdown will occur in any location where that temperature is exceeded. The bulk temperature of the fluid in the reservoir means very little.

RE: Actual test of engine oils...

There are a bunch of companies that can replate the cylinders. Powerseal, Millennium Technologies, US Chrome, Electro-coatings, etc... I had terrible experience with Us Chrome. Not all of the companies can do a monoblock engine but I think your bike is not (has a separate cylinder block).

RE: Actual test of engine oils...

(OP)
Oops! Krytox may not work as a replacement for engine oil in cooling cylinder walls and other engine surfaces. Per http://www2.eng.cam.ac.uk/~mpfs/papers/articles/WT... petroleum oils at 38C (100F) have thermal conductivity near 0.125 and heat capacity near 2.1 while Krytox has conductivity of 0.88 and heat capacity of 0.98 at the same temperature. For comparison, water has conductivity of 0.625 and capacity of 4.25 at the same temperature. Unless I got the units wrong, when comparing the Krytox spec at http://www2.dupont.com/Lubricants/en_US/assets/dow... with the paper used for the other figures, the utility of Krytox in cooling is much poorer than regular oil.

RE: Actual test of engine oils...

Follow-up to a sidetrack on this thread. First test-ride of the above-mentioned ZX10R engine was yesterday with the objective of getting the initial break-in done. I put about 40 km on it, then changed the oil and filter. I have a magnetic drain plug in the engine, and it collected a wee bit of black magnetic slime ... hopefully, evidence of piston-ring break-in. It ran well.

RE: Actual test of engine oils...

(OP)
Congratulations Brian! I hope it hangs in there for you!

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